Synthesis, characterization, and photophysical properties of some heterodimetallic bisporphyrins of ytterbium and transition metals -: Enhancement and lifetime extension of Yb3+ emission by transition-metal porphyrin sensitization

A series of d-f heterodimetallic bisporphyrin complexes (YbZn, YbPd, and YbPt), in which a Yb-III porphyrinate moiety is linked to a transition-metal porphyrinate moiety by a flexible three-carbon chain, were synthesized. They were fully characterized by high-resolution mass spectrometry, H-1 and P-31 NMR spectroscopy, electronic absorption, and fluorescence methods. Variable-temperature near-infrared photoluminescence studies showed that the transition-metal porphyrinate moiety would enhance the ytterbium(III) emission centered at about 998 nm and extend its emission life-time. YbPd and YbPt showed large two-photon absorption cross-section values because of the interaction between the porphyrin units, which caused a loss of centrosymmetry. Optical limiting investigation demonstrated that [Yb(TPP)-(L-OMe)] and YbPt have comparable performance to C-60 by virtue of their heavy-metal effect. Our results indicate that these bisporphyrin dimetallic complexes will find valuable applications in the field of nonlinear optics. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).